We are updating the forums to IPB 3.4.6 this morning. The update will commence within the next hour or two, whenever Redmak feels comfortable to throw the switch.
As you may know, our upgrade path is... complex to say the least. Our board is largely customized, which means we can't just run the upgrade script and be on our merry way, no.. we have to modify the upgrade script so that all of our own code level hacks don't get overwritten.
So expect some downtime on the forums, do check out the main page or something in the meantime.
Upgrade is expected to take about an hour.